Glycine rejuvenates old cells in test tubes, we wrote four years ago. However, that study is not the only indication that glycine may be an interesting longevity supplement. American aging researchers at the University of Michigan gave mice a hefty dose of glycine throughout their lives, and discovered that it made the animals live longer.

Study

The researchers gave a group of laboratory mice from the age of nine until they died of diet that consisted of 8 percent glycine. We estimate that if the mice in the experimental group were humans, they would have received 100-140 grams of glycine per day. Another group received standard food without special additives.

One ounce of glycine a day is a lot. It is more than possible that, in such quantities, glycine causes side effects. To be honest, we also wonder whether such astronomical dosages are necessary.

There are indications that glycine is a semi-essential amino acid. The body makes glycine by converting other amino acids, but under certain circumstances the need for glycine exceeds the amount of glycine the body is able to synthesize. Supplementation with 10 grams of glycine per day should eliminate this problem.

For life extensionists, this 10 grams per day is perhaps a better dose than 100-140 grams per day.

Results
Both the male and female mice that received glycine lived longer than the lab mice that received standard chow. Glycine supplementation prolonged life by 4-6 percent. Not much, but statistically significant.

The female mice lost body weight due to glycine; the male mice didn't. The researchers could not explain why.

Mechanism

"The mechanism of effect is not yet known and will require additional targeted work, but could conceivably involve lowered inflammation in one or more tissue beds, or effects of glycine on CNS processes, or effects, direct or indirect, on multiple forms of lethal neoplastic disease", write the researchers.

Conclusion
"Our most interesting new finding is that glycine-supplemented diets extend lifespan of [...] mice, including significant benefits in lifespan to mice at the 90th percentile age", the researchers summarize.

"The effect in mice [..] is quite small and does not much alter median survival age. We speculate that variations in this protocol, for example, in which glycine supplementation is started earlier or terminated once mice are fully grown, might have improved effects on health and lifespan."